The fundamental purpose of these investigations is to study the fetal uptake and distribution of local anesthetics used in obstetrical anesthesia. The investigations are designed to study: 1. Total fetal uptake and the rate of uptake of local anesthetic agents as they relate to physicochemical properties. 2. The degree to which a maternal-fetal concentration equilibrium occurs. 3. The factors that affect the fetal-to-maternal concentration ratios. 4. The fetal tissue distribution of local anesthetics to vital organs. 5.The fetal protein binding for commonly used local agents not already evaluated. These studies will provide valuable information regarding the distribution of local anesthetics in the fetus and help to evaluate the quantity and distribution of these agents that extend into the neonatal period.